How must I adapt my workflow to work with Scene Referred Data?
I'm a little bit lost.


Don't be. Just learn a little bit at a time and build up your knowledge in smaller steps. We are all learning more at every moment.

I laughed at the red pill.


  But now, how and what must I change in my workflow to really benefit of working with scene referred data?


There isn't too much to get too swamped with too soon. Start by experimenting with how larger amounts of light influence your materials.

To do this, simply use an emission mesh with a wide dynamic range view transform. That is, if you are using the testing kit I put together for example, the -10-+6.5 view. You will need to set the emission strength quite high as compared to what you were using under the "Default" previously.

Typical questions and concerns are:


"It looks washed out!"
"How can I control the look?"


The reason the image looks 'washed out' is that it is mapping of scene referred values to the display referred domain, and there is a very wide range to map. To achieve this, a "shaper" or "perceptual quantizer" mapping happens. This is typically a 'flat' look in terms of an artistic sense. While not an aesthetic look for a final shot, it is a wonderful entry point to evaluate your data for a grade.

Once you have rendered out a simple shot, try grading it. I strongly recommend doing a simple, single node grade using the CDL node. It is in the Color Balance node. Simply change from the Lift, Gamma, Gain (which does not work with scene referred data) to ASC-CDL.

The reasons for this are many, and it is a forward looking tool to learn. It is also very easy to get to a pleasant looking shot simply by adjusting power up (1.5-2.5) and slightly adjusting the Slope downwards slightly. Remember that shift key can help you use the interactive sliders on the RGB values with small increments.

0.18 middle grey scene referred ends up mapped to 0.6 in the display referred -10-+6.5 view. You probably would want to grade this down a little, although that will happen naturally when you tweak the power and the slope.


  Is my hdr lighting well suited for that workflow?


HDR and IBL lighting is well suited for the workflow, assuming the HDRs are correct and have the proper range of values. This can be tricky to find good quality images. EXR are ideal.


  Must i have to throw all my rgb textures and only find exr ones?


Some textures will behave brokenly with proper light levels. This isn't because using a wide dynamic range broke them however, but rather that they were broken to start. If you are using an emission, then you must use scene referred imagery. Diffuse textures and such are not "colors" per se, but rather albedo values, which are a measurement of reflectance. Given that nothing reflects at 100% in the physical reality, diffuse textures of sRGB values 1.0 will likely lead to very strange results, for example.

There are a good number of very talented and wise people here, that you might be able to summon to help you learn. @jtheninja and @gez are two folks with good experience on materials for example.

Hope this helps. Take small steps and hopefully you will enjoy the results.

For the ones interested by the subject, check the Wide Dynamic Range post